Third generation partnership project (3GPP) mobile communication systems based on a wideband code division multiple access (WCDMA) radio access technology are widely spread all over the world. High-speed downlink packet access (HSDPA) that can be defined as a first evolutionary stage of WCDMA provides 3GPP with a radio access technique that is highly competitive in the mid-term future. However, since requirements and expectations of users and service providers are continuously increased and developments of competing radio access techniques are continuously in progress, new technical evolutions in 3GPP are required to secure competitiveness in the future.
In general, there are one or more cells within the coverage of a base station (BS). A plurality of user equipments (UEs) may be located in one cell. When a UE attempts an initial access to a new cell, the UE is downlink synchronized, and receives system information (or simply referred to as SI) from a network to be accessed. The SI includes necessary information which needs to be known to the UE in order to communicate with the BS. Thus, the UE has to entirely receive the SI before accessing to the BS, and has to always maintain the latest SI. The BS informs the UE of a plurality of pieces of basic information required to access to the network by using the SI.
The SI includes various SI parameters. In general, the BS distributively transmits the SI parameters according to a defined transmission period instead of concurrently transmitting the entire SI parameters. The BS has to inform the UE of scheduling information for transmitting the SI parameters. The UE monitors the SI according to the scheduling information of the SI. If there is no accurate scheduling information of the SI, the UE has to persistently monitor the SI, which may lead to unnecessary power consumption.
Accordingly, there is a need to inform the accurate scheduling information of the SI so that the UE can further effectively obtain the SI.